As a contact mechanism of the rotating-pressing operation type electronic part used in the portable telephone, for example, there is conventionally a structure in which a common elastic contact 39A and elastic contacts 39B, 39C for a signal come in contact with an electrically conductive portion arranged in a radiating shape on the surface of a radiating contact plate 38 as shown in patent literature 1 so that a rotating direction and a rotating amount of a columnar operation knob 26 are detected (see FIG. 27B).
Further, as shown in patent literature 2, there is a structure in which an insulating portion 54 and an electrically conductive portion 55 are alternately arranged at a predetermined angle pitch on the outer circumferential face of a columnar portion 40A, and a rotating direction and a rotating amount of a columnar operation knob 42 are detected by plural elastic contact legs 37 coming in contact with the insulating portion 54 and the electrically conductive portion 55 (see FIG. 27C).                Patent literature 1: JP-A-2000-251584        Patent literature 2: JP-A-2001-283685        